Antenna with core, mainly miniature RFID and/or NFC antenna, and method of its production

Abstract

Part of the conductive loop of the threads is formed by a printed circuit on the substrate ( 5 ), where the group of the conductive strips ( 2 ) placed side by side is produced, and the core ( 1 ) is placed on them. The conductive strips ( 2 ) overhang from the groundplan of the core ( 1 ) and the ends of the conductive strips ( 2 ) overhanging on both sides of the core ( 1 ) form the connecting surfaces ( 4 ). The wires ( 3 ) shaped for the encirclement of the core ( 1 ) are connected to the connecting surfaces ( 4 ), whereby the wire ( 3 ) connects a connecting surface ( 4 ) of one conductive strip ( 2 ) with the connecting surface ( 4 ) on the opposite end of the neighboring conductive strip ( 2 ). After bonding to one end of the conductive strip ( 2 ) the wire is shaped above the substrate ( 5 ) by bending in such a way that it arches over the space intended for the core ( 1 ) and all wires ( 3 ) are shaped in such a way that they produce a channel for the core ( 1 ) placed on the substrate ( 5 ). The conductive strips ( 2 ) are sloped from the normal of the core ( 1 ) under an angle pursuant to the pitch of the thread and the wires ( 3 ) are led in the opposite slope under the same angle.

The invention claimed is: 
     
       1. An antenna with a core where conductive loops encircle an oblong core ( 1 ) placed on a non-conductive substrate ( 5 ), and where part of the conductive loop is formed by a printed circuit on the substrate ( 5 ), the antenna comprising:
 a group of conductive strips ( 2 ) placed side by side on the substrate; 
 the core ( 1 ) is placed on the conductive strips ( 2 ); 
 the conductive strips ( 2 ) overhang from a ground plane of the core ( 1 ) in such a way that ends of the conductive strips ( 2 ) overhanging on both sides of the core ( 1 ) form connecting surfaces ( 4 ); 
 wires ( 3 ) shaped for an encirclement of the core are connected to the connecting surfaces ( 4 ); 
 wherein the wire ( 3 ) connects the connecting surface ( 4 ) of one conductive strip ( 2 ) to the connecting surface ( 4 ) on the opposite end of the neighboring conductive strip ( 2 ); 
 the wire ( 3 ) has a width forming 50% to 100% of the width of the conductive strip ( 2 ) and the wire ( 3 ) has a flat or an oval cross-section; 
 wherein the antenna is a miniature RFID antenna or a NFC antenna. 
 
     
     
       2. The antenna according to the  claim 1 , wherein the conductive strips ( 2 ) are parallel to each other. 
     
     
       3. The antenna according to  claim 1 , wherein the wire ( 3 ) is bonded to the connecting surface ( 4 ) by a wedge bonding. 
     
     
       4. The antenna according to  claim 1 , wherein the wire ( 3 ) has a width which is more than twice its thickness. 
     
     
       5. The antenna according to  claim 1 , wherein the connecting surface ( 4 ) of one conductive strip ( 2 ) is connected with the opposite connecting surface ( 4 ) of the neighboring conductive strip ( 2 ) by at least two wires ( 3 ) led in parallel. 
     
     
       6. The antenna according to  claim 1 , wherein the substrate ( 5 ) is formed by an independent pad whose ground plane dimensions correspond to the group of the conductive strips ( 2 ), or the substrate ( 5 ) is formed by a PCB with other components. 
     
     
       7. The antenna according to  claim 1 , wherein the core ( 1 ) in the cross-section has a height up to 0.5 mm and a width in a cross-section ranging from 2 to 2.5 mm. 
     
     
       8. The antenna according to  claim 1 , wherein the conductive strips ( 2 ) are sloped from the ground plane normal of the core ( 1 ) under an angle corresponding to a pitch of threads and the wires ( 3 ) are led in the opposite slope with the same size of the angle. 
     
     
       9. The antenna according to  claim 1 , wherein the conductive strips ( 2 ) overhang on each lateral side of the core ( 1 ) in a length which is at least 5% of a transversal dimension of the core ( 1 ); at minimum they overhang in the length at least 0.25 mm. 
     
     
       10. The antenna according to  claim 1 , wherein:
 the end of the wire ( 3 ) in a place of joint with the connecting surface ( 4 ) runs in parallel with a plane of the substrate ( 5 ) and it is oriented in a direction out from the core ( 1 ); or 
 the wire ( 3 ) in the place of joint with the connecting surface ( 4 ) is “S” shaped, whereby three layers of the wire ( 3 ) are placed above each other in the place of joint. 
 
     
     
       11. The antenna according to  claim 1 , wherein the core ( 1 ) is at least partially embedded in a groove in the substrate ( 5 ); the conductive strips ( 2 ) run from a bottom of the groove up on lateral walls of the groove and they are ended by the connecting surfaces ( 4 ) on a upper surface of the substrate ( 5 ). 
     
     
       12. The antenna according to  claim 1 , wherein the antenna is placed on or in the substrate ( 5 ) of a removable memory card with a contact interface. 
     
     
       13. The antenna according to  claim 12 , wherein the removable memory card is microSD card or SIM card or mini-SIM card or nano-SIM card. 
     
     
       14. The antenna according to  claim 1 , wherein the wires ( 3 ) are glued on a foil ( 8 ). 
     
     
       15. The antenna according to  claim 1 , wherein between the wires ( 3 ) and the core ( 1 ) and/or between the core ( 1 ) and the conductive strips ( 2 ) there is a gap ( 7 ). 
     
     
       16. A method of a production of the antenna with a core comprising the steps of:
 placing side by side a group of independent conductive strips ( 2 ) on a non-conductive substrate wherein a number of the conductive strips ( 2 ) corresponds to a number of conductive loops of the antenna; 
 welding on an end of the wire ( 3 ) by the bonding on one end of the conductive strip ( 2 ) and a second end of the wire ( 3 ) is welded to the opposite end of the neighboring conductive strip ( 2 ), 
 placing the core ( 1 ) on the non-conductive substrate ( 5 ) before bonding the wires ( 3 ) or placing the core ( 1 ) on the non-conductive substrate ( 5 ) after the bonding of the wires ( 3 ); 
 repeating subsequently the bonding of the wires ( 3 ) for all conductive loops of the antenna which connects all conductive strips ( 2 ) behind each other 
 wherein after the bonding to one end of the conductive strip ( 2 ) the wire ( 3 ) is shaped above the substrate ( 5 ) by a bending in such a way that it arches over a space intended for the core ( 1 ) and all the wires ( 3 ) are shaped in such a way that they produce a channel for the core ( 1 ) placed on the substrate ( 5 ), whereby the flat or oval wire ( 3 ) is bonded; 
 wherein the core ( 1 ) is inserted from a side to the channel between the shaped wires ( 3 ) and the non-conductive substrate ( 5 ); and 
 wherein the antenna is a miniature RFID antenna or a NFC antenna. 
 
     
     
       17. The method according to  claim 16  wherein the bonding of the wires ( 3 ) takes place in a phase when other components are bonded on the PCB of the host device. 
     
     
       18. The method according to  claim 16 , wherein multiple wires ( 3 ) are bonded from the single connecting surface ( 4 ), the wires ( 3 ) then connect the connecting surface ( 4 ) of the single conductive strip ( 2 ) with the connective surface ( 4 ) of the neighboring conductive strip ( 2 ). 
     
     
       19. The method according to  claim 16  wherein the wire ( 3 ) is bonded by wedge bonding. 
     
     
       20. The method according to  claim 19 , wherein all wires ( 3 ) on one side of the core ( 1 ) are bonded in the first step and all wires ( 3 ) on the other side of the core ( 1 ) are bonded in the second step.